1. Field of the Invention
The present invention relates to an absorbent article for absorbing body fluids and exudates, such as urine. More particularly, the present invention relates to absorbent garments, such as disposable diapers and adult incontinence garments, which are configured to absorb body exudates while not adversely affecting the temperature of the wearer""s skin.
2. Description of the Related Art
Many known diaper configurations employ absorbent materials located between a liquid pervious topsheet and a vapor and liquid impermeable backsheet. Such backsheets are well suited to prevent the migration of liquid waste from the absorbent materials to the outer garments of a wearer. Unfortunately, the use of liquid and vapor impermeable backsheets can result in a high degree of humidity within the diaper when in use which may increase the temperature of the wearer""s skin and result in relatively high skin hydration levels. The occlusive, moist environment inside diapers incorporating such backsheets can promote the viability of microorganisms, including Candida albicans, which can undesirably lead to the onset of diaper dermatitis (diaper rash).
Diaper dermatitis can afflict almost every infant at some time during the diaper wearing years. The most severe form of this condition is usually caused by secondary infection with the fungi Candida albicans. Although other factors influence the pathogenesis of this fungi, one critical factor is the relative humidity within the diaper which is directly related to the occlusion or semi-occlusion of the diaper area.
In order to reduce the humidity level within diapers, breathable polymer films have been employed as outer covers for absorbent garments, such as disposable diapers. The breathable films are typically constructed with micropores to provide desired levels of liquid impermeability and air permeability. Other disposable diaper designs have been arranged to provide breathable regions in the form of breathable panels or perforated regions in otherwise vapor-impermeable backsheets to help ventilate the garment.
Conventional absorbent articles, such as those described above, have not been completely satisfactory. For example, articles which employ perforated films or breathable panels can exhibit excessive leakage of liquids from the article and can excessively soil the wearer""s outer garments in the regions of the perforations or panels. In addition, when the absorbent material of the article becomes loaded with liquid, the wet absorbent can block the escape of moisture from the wearer""s skin. Such absorbent garment designs have not been able to maintain a high level of breathability when wet to sufficiently reduce the hydration of the wearer""s skin. As a result, the wearer""s skin has remained susceptible to rashes, abrasion and irritation.
In response to the difficulties and problems discussed above, a new disposable absorbent article which has a high air exchange rate when wet, maintains skin temperature when wet, has reduced levels of skin hydration and has a reduced viability of microorganisms has been discovered.
As used herein, reference to xe2x80x9cair exchangexe2x80x9d refers to the transfer of air from the interior of a diaper, when in use on a wearer, to the exterior of the diaper (ambient atmosphere).
As used herein, a substantially liquid impermeable material is constructed to provide a hydrohead of at least about 60 cm (centimeters), desirably at least about 80 cm, and more desirably at least about 100 cm. A suitable technique for determining the hydrohead value is the Hydrostatic Pressure Test which is described in further detail herein below.
As used herein, a substantially vapor permeable material is constructed to provide a water vapor transmission rate (WVTR) of at least about 100 g/sq.m/24 hr, desirably at least about 250 g/sq.m/24 hr, and more desirably at least about 500 g/sq.m/24 hr. A suitable technique for determining the WVTR value is the Water Vapor Transmission Rate Test which is described in further detail herein below.
In one aspect, the present invention relates to an absorbent article which comprises an absorbent, a front waist section, a rear waist section and an intermediate section which interconnects the front and rear waist sections. The absorbent article defines a Wet Air Exchange Rate of at least about 190 cubic centimeters per minute calculated according to the Tracer Gas Test set forth herein. In a particular embodiment, the article defines a Wet Air Exchange Rate of at least about 200, desirably at least about 225 and more desirably at least about 250 cubic centimeters per minute calculated according to the Tracer Gas Test. The absorbent article may further define a Dry Air Exchange Rate of at least about 525 cubic centimeters per minute calculated according to the Tracer Gas Test and/or a Skin Hydration Value of less than about 18 grams per square meter per hour calculated according to a Skin Hydration Test set forth herein.
In another aspect, the present invention relates to a disposable absorbent article which comprises an absorbent, a front waist section, a rear waist section and an intermediate section which interconnects the front and rear waist sections. The absorbent article defines a Skin Hydration Value of less than about 18 grams per square meter per hour calculated according to the Skin Hydration Test set forth herein. In a particular embodiment, the absorbent article may define a Skin Hydration Value of less than about 15, desirably less than about 12 and more desirably less than about 10 grams per square meter per hour calculated according to the Skin Hydration Test. The absorbent article may further define a Wet Air Exchange Rate of at least about 190 cubic centimeters per minute and/or a Dry Air Exchange Rate of at least about 525 cubic centimeters per minute calculated according to the Tracer Gas Test as set forth herein.
In another aspect, the present invention relates to a disposable absorbent article which defines a front waist section, a rear waist section, and an intermediate section which interconnects the front and rear waist sections. The absorbent article includes a) a vapor permeable backsheet which defines a Water Vapor Transmission Rate of at least about 1000 grams per square meter per 24 hours calculated according to a Water Vapor Transmission Test as set forth herein; b) a liquid permeable topsheet which is positioned in facing relation with the backsheet; and c) an absorbent body located between the backsheet and the topsheet which may define multiple zones of high air permeability for improved air exchange. In a particular embodiment, the zones of high air permeability in the absorbent body define a Frazier Porosity which is at least about 10 percent greater than a Frazier Porosity of portions of the absorbent body adjacent to the zones of high air permeability. The absorbent article may further include a ventilation layer located between the backsheet and the absorbent body.
In still another aspect, the present invention relates to a disposable absorbent article which defines a front waist section, a rear waist section, and an intermediate section which interconnects the front and rear waist sections. The absorbent article includes a) a vapor permeable, liquid impermeable backsheet which defines a Water Vapor Transmission Rate of at least about 1000 grams per square meter per 24 hours calculated according to a Water Vapor Transmission Test as set forth herein; b) a liquid permeable topsheet which is positioned in facing relation with the backsheet; c) an absorbent body located between the backsheet and the topsheet; d) a ventilation layer located between the backsheet and the absorbent body; and e) a surge management layer located between the topsheet and the absorbent body. In a particular embodiment, the absorbent body of the absorbent article includes a plurality of zones of high air permeability for improved air exchange which define a Frazier Porosity which is at least about 10 percent greater than a Frazier Porosity of portions of the absorbent body adjacent to the zones.
In yet another aspect, the present invention relates to a disposable absorbent article which includes an absorbent, a front waist section, a rear waist section and an intermediate section which interconnects the front and rear waist sections. The absorbent article defines a C. albicans viability which is less than about 85 percent of the C. albicans viability of a control calculated according to a C. albicans Viability Test as set forth herein. In a particular embodiment, the C. albicans viability is less than about 80 percent and desirably less than about 60 percent of the C. albicans viability of the control calculated according to the C. albicans Viability Test. The absorbent article may further define a Wet Air Exchange Rate of at least about 190 cubic centimeters per minute and/or a Dry Air Exchange Rate of at least about 525 cubic centimeters per minute calculated according to the Tracer Gas Test as set forth herein and/or a Skin Hydration Value of less than about 18 grams per square meter per hour calculated according to the Skin Hydration Test set forth herein.
In another aspect, the present invention relates to a disposable absorbent article which comprises an absorbent, a front waist section, a rear waist section and an intermediate section which interconnects the front and rear waist sections. The absorbent article defines a Wet Skin Temperature/Dry Skin Temperature Ratio of no more than about 1.010 calculated according to a Skin Temperature Test as set forth herein. In particular embodiments, the absorbent article defines a Wet Skin Temperature/Dry Skin Temperature Ratio of no more than about 1.005, desirably no more than about 1.000, more desirably no more than about 0.995, and even more desirably no more than about 0.990 calculated according to the Skin Temperature Test. The absorbent article may is further define a Wet Air Exchange Rate of at least about 190 cubic centimeters per minute and/or a Dry Air Exchange Rate of at least about 525 cubic centimeters per minute calculated according to the Tracer Gas Test as set forth herein and/or a Skin Hydration Value of less than about 18 grams per square meter per hour calculated according to the Skin Hydration Test set forth herein.
The present invention advantageously provides improved absorbent articles which exhibit substantially reduced levels of hydration of the wearer""s skin when in use compared to conventional absorbent articles. The reduced level of skin hydration promotes drier, more comfortable skin and renders the skin less susceptible to the viability of microorganisms. Thus, wearer""s of absorbent articles made according to the present invention have reduced skin hydration and more constant skin temperatures in use which can lead to a reduction in the incidence of skin irritation and rash.